In-room imaging and MR planning

Myocardial Perfusion

• Many limitations:

– Motion. Synchronization with ECG. Breath-hold. – Must be done in stress conditions. High HR. Increase of motion. need to increase acquisition time. Systolic phase. – Synchronization with ECG seriously limits sampling time. – If a big coverage (16 cm) is not available, the shuttle mode must be used: sampling time further reduced by half. – BF is really fast in the myocardium (~ 300 mL / min  100 mL). Normally such values cannot easily be obtained with such low temporal sampling (~3 to 4 s), thus some models derived from Tofts are normally employed to calculate PS and backflow, capillaries volume etc. BF is then calculated with MS models. – Backflow occurs very quickly, so models assuming no backflow (like Patlak) are not suitable to this application. – Beam hardening artifacts in myocardium (limitation on how low the kV can be set).